Betta: basic information / help

Question
I received a betta as a gift about 2 months ago and was very unsure about how to take care of it. I found a lot of information on the Internet, most of it was conflicting with what I heard from other sources. Originally the betta was in a very small container the package claimed he could be kept in. I wasn't so sure.
    The Betta looked very unhappy so I put him in a larger  1 gallon bowl, which he seemed very happy with, in comparison. The bowl only contains water. I feed him pellets currently twice daily. I change the water weekly and remove his excretions daily with a turkey baster. when I change the water I replace it with bottled spring water because the local water is very hard. I do not use a filter or heater.
    Currently my Betta has been looking a bit down. First, a couple weeks ago I noticed the color on top of his head was darkening; when I looked on he Internet for advice it said that  the fish darken with age so I dismissed it. Today, my fish is a bit sluggish (normally he is a spaz). his beautiful fins are slightly curdled at the ends and it looks like the color is fading to a white from mouth to gills on the bottom half of his head
    I would appreciate it if you could tell me the proper method of taking care of my betta.

Answer
Kitty,
A one gallon bowl is not the right home for him. The smallest home is 2.5 gallons, where a 5 gallon is best. He is also a tropical fish and his water needs to be between 80 and 82 degrees at all times. Once you get him in the right size home, with a heater, you should see a big difference in him. It also sounds like he has fin rot. You can add some dissolved aquarium salt to his water at a ratio of 1 teaspoon per 1 gallon. The salt water is only added during a water change. Make sure the salt is dissolved before you put the water or it will burn him. Salt does not evaporate so once his fin rot is gone you will have to start removing the salt water by doing 25% water changes daily for about 4 to 5 days.